High-Performance Solution-Processable Organic Light-Emitting Diode Based on a Narrowband Near-Ultraviolet Emitter and a Hot Exciton Strategy

• Published in: Angewandte Chemie International Edition 2024-12, p.e202421520
• Main Authors: Jiang, Kai, Chang, Xiang, Zhu, Jieqiong, Zhu, Tian, Yu, Junting, Wang, Yafei, Zhang, Youming, Ma, Dongge, Zhu, Weiguo
• Format: Article
• Language: English
• ISSN: 1521-3773; 1521-3773
• DOI: 10.1002/anie.202421520

Achieving high efficiency narrowband near-ultraviolet (NUV) emitters in organic light emitting diode (OLED) is still a formidable challenge. Herein, a proof-of-concept hybridized local and charge transfer (HLCT) molecule, named ICz-BO, is prepared and characterized, in which both multiresonant (MR) skeletons are integrated via conjugation connection. A slightly distorted structure and weak intramolecular charge transfer (CT) interaction between two MR subunits lead to a high-lying reverse intersystem crossing (h-RISC) channel of T →S , also evidenced by both experimental and calculated results. Impressively, the ICz-BO emitter exhibits outstanding narrowband NUV emission at 404 nm with a full-width at half maximum of 28 nm in toluene solution. The solution processable OLED shows an excellent device performance with the recorded maximum external quantum efficiency of 12.01 %, concomitant with an extremely low y-axis Commission Internationale de l'Éclairage (CIE ) value of 0.031. To the best of our knowledge, this is the highest efficiency reported for the HLCT-based NUV-OLEDs to date. This research proves that the MR skeleton plays a positive effect on the narrowband hot exciton emitter, which provides an alternative paradigm for developing high-efficiency NUV emitters.